In many metropolitan areas, most selective call systems are operated at, or near, the maximum system capacity, in both the number of subscribers that can be accommodated, and the message transmission time that is available. Such selective call system operation has resulted in reduced customer satisfaction due to extended times required to access the selective call system, and extended delays in message delivery due to equally extended selective call system message transmission queues. At present, this need is being offset by increasing the data rate of the protocol used.
To further aggravate the problem, the limited radio spectrum available worldwide or nationwide makes it challenging to provide seamless communication to and from pagers. It has become necessary to equip pagers with frequency synthesizers to enable them to scan or select among a plurality of frequencies within the available selective call spectrum when the pagers are roaming or have lost their signal. However, because there are a limited number of available selective call frequencies, no significant system expansion can be achieved or expected although there is a significant increase in the message length and the number of subscribers.
Thus, what is needed is a paging system that can improve message delivery by penetrating existing cellular communication systems without changing the paging protocol or cellular protocol and without requiring any more dedicated selective call frequency allocations.